Microsporidia: Pathogens of Opportunity -- Copyright -- Contents -- Contributors -- Preface -- Acknowledgments -- Chapter 1 Structure of Microsporidia -- 1.1 INTRODUCTION -- 1.2 STRUCTURAL CHARACTERS AND CLASSIFICATION OF MICROSPORIDIA -- 1.2.1 Microsporidia under the Light Microscope -- 1.3 STRUCTURAL ASPECTS OF REPRODUCTION AND LIFE CYCLES -- 1.3.1 Basic Life Cycle -- 1.3.2 Reproduction Modes -- 1.3.3 Sexual Processes -- 1.3.4 Life Cycle Types -- 1.4 ESSENTIALS OF MICROSPORIDIAN CYTOLOGY -- 1.4.1 The Plasma Membrane -- 1.4.2 The Nucleus -- 1.4.3 Mitosomes -- 1.4.4 Endoplasmic Reticulum -- 1.4.5 Ribosomes -- 1.4.6 Golgi Apparatus -- 1.5 STRUCTURE OF MICROSPORIDIAN DEVELOPMENTAL STAGES -- 1.5.1 The Spore -- 1.5.2 Meronts and Merozoites -- 1.5.3 Sporogony -- 1.5.4 The Sporoblast -- 1.5.5 The Origin of the Extrusion Apparatus -- 1.6 THE MATURE SPORE -- 1.6.1 Spore Shape -- 1.6.2 Spore Size -- 1.6.3 The Spore Wall -- 1.6.4 The Plasma Membrane -- 1.6.5 The Nucleus -- 1.6.6 Cytoplasmic Organelles -- 1.6.7 The Polar Filament -- 1.6.8 The Polaroplast -- 1.6.9 The Posterior Vacuole -- 1.7 ENVELOPES OF MICROSPORIDIAN ORIGIN -- 1.7.1 Sporophorous Vesicles -- 1.7.2 Exospore-Derived Envelopes -- 1.7.3 Sporont-Derived Sacs -- 1.7.4 Parasitophorous Vacuole as Envelope of Parasite Origin? -- 1.8 CYTOLOGICAL ANOMALIES IN MICROSPORIDIA -- 1.9 MICROSPORIDIA-INDUCED EFFECTS ON HOST CYTOLOGY -- 1.9.1 Association with Host Cell Organelles -- 1.9.2 The Parasitophorous Vacuole as Host Cell Product? -- 1.9.3 Host Cell Hypertrophy -- 1.9.4 Infections of the Digestive Tract Epithelium -- 1.10 COMMENTS ON THE STRUCTURE OF SOME HUMAN OPPORTUNISTIC MICROSPORIDIA -- 1.10.1 Enterocytozoon bieneusi -- 1.10.2 Encephalitozoon Species -- 1.10.3 Trachipleistophora Species -- 1.10.4 Vittaforma corneae -- 1.10.5 Human Pathogenic Microsporidia of the Family Tubulinosematidae.

1.11 STRUCTURE-RELATED TECHNIQUES IN MICROSPORIDIA RESEARCH -- 1.11.1 Recognizing Infected Hosts and Making Diagnostic Smears -- 1.11.2 Recognizing Microsporidian Spores -- 1.11.3 Observation and Measuring of Microsporidian Spores -- ACKNOWLEDGMENTS -- REFERENCES -- Chapter 2 Developmental Morphology and Life Cycles of the Microsporidia -- 2.1 INTRODUCTION -- 2.2 MICROSCOPIC IDENTIFICATION OF SPORES BY LIGHT AND ELECTRON MICROSCOPY -- 2.3 LIFE CYCLE -- 2.3.1 Phase I of the Microsporidian Life Cycle, Environmental and Infective -- 2.3.2 General Spore Structure -- 2.3.3 Spore Germination -- 2.3.4 Polar Filament Extrusion -- 2.3.5 Spore Activation -- 2.3.6 Polar Tube Eversion and Transit from the Spore -- 2.3.7 Sporoplasms -- 2.3.8 Sporoplasm Transfer and Infection -- 2.3.9 Polar Tube Proteins -- 2.4 INTRACELLULAR MICROSPORIDIAL DEVELOPMENT AND INTERFACIAL RELATIONSHIPS -- 2.4.1 Type I: Microsporidia considered to have Direct Contact -- 2.4.2 Type II: Microsporidia with Parasite-Produced Interfacial Envelopes -- 2.4.3 Type III: Microsporidia with Host-Produced Interfacial Envelopes -- 2.4.4 Type IV: Microsporidia with Indirect Contact by Host- and Parasite-Produced Interfacial Envelopes -- 2.5 APPENDAGES -- 2.6 Phase II of Microsporidia Life Cycle -- 2.6.1 Proliferative Cells -- 2.6.2 Nucleation and Nuclear Activity -- 2.6.3 Nuclear Division -- 2.6.4 Cytokinesis -- 2.7 Phase III of Microsporidia Life Cycle, Sporogony -- 2.7.1 Sporonts -- 2.7.2 Sporoblasts -- 2.7.3 Sporogony in the Enterocytozoonidae -- 2.8 SPORES -- 2.8.1 Spore Coat -- 2.8.2 Extrusion Apparatus -- 2.8.3 Spores Types -- 2.8.4 Variations within a Species -- 2.9 SUMMATION -- REFERENCES -- Chapter 3 Epidemiology of Microsporidia in Human Infections -- 3.1 INTRODUCTION -- 3.2 INFECTIOUS DOSE AND NUMBER OF SPORES EXCRETED -- 3.3 SOURCES OF TRANSMISSION -- 3.3.1 Trauma and Ocular Infection.

3.3.2 Waterborne Transmission and Environmental Survival -- 3.4 FOODBORNE TRANSMISSION -- 3.4.1 Presence in Fresh Produce and Juice -- 3.4.2 Foodborne Outbreak -- 3.4.3 Disinfection of Contaminated Produce -- 3.5 AIRBORNE TRANSMISSION -- 3.6 VECTORS AND ZOONOTIC SOURCES -- 3.6.1 Insect Sources -- 3.6.2 Possible Fish Sources -- 3.6.3 Birds -- 3.6.4 Companion Animals -- 3.7 LIVESTOCK -- 3.7.1 Cattle -- 3.7.2 Pigs -- 3.7.3 Other Farmed Animals -- 3.8 PERSON-TO-PERSON TRANSMISSION -- 3.9 INFLUENCE OF AGE -- 3.10 IMMUNOCOMPROMISED POPULATIONS -- 3.10.1 Organ Transplant Patients -- 3.10.2 HIV Patients -- 3.10.3 Neoplastic Disease -- 3.11 MOLECULAR EPIDEMIOLOGY -- 3.11.1 E. bieneusi -- 3.11.2 E. cuniculi -- 3.11.3 E. hellem -- 3.11.4 E. intestinalis -- REFERENCES -- Chapter 4 Epizootiology of Microsporidiosis in Invertebrate Hosts -- 4.1 INTRODUCTION -- 4.2 MONITORING MICROSPORIDIAN EPIZOOTICS IN INVERTEBRATE HOSTS -- 4.3 MOLECULAR TOOLS HAVE ADVANCED THE STUDY OF MICROSPORIDIAN DISEASE AND EPIZOOTIOLOGY -- 4.4 PREVALENCE AND INCIDENCE OF MICROSPORIDIAN DISEASE IN INVERTEBRATE POPULATIONS -- 4.5 COMPONENTS OF MICROSPORIDIAN EPIZOOTIOLOGY IN INVERTEBRATE ANIMALS -- 4.5.1 The Pathogen Population -- 4.5.2 Infectivity, Pathogenicity, and Virulence -- 4.5.3 Infectivity -- 4.5.4 Virulence -- 4.5.5 Survival and Persistence of Microsporidia -- 4.5.6 Survival of Terrestrial Microsporidia -- 4.5.7 Survival of Aquatic Microsporidia -- 4.5.8 Dispersal Mechanisms -- 4.6 HOST POPULATION -- 4.6.1 Age and Stage Susceptibility to Microsporidia -- 4.6.2 Natural Invertebrate Population Density and Fluctuations -- 4.6.3 Environment and Other Abiotic Factors -- 4.7 HOST-MICROSPORIDIA INTERACTIONS -- 4.7.1 Tissue Tropism of Microsporidia -- 4.8 TRANSMISSION -- 4.8.1 Horizontal Transmission -- 4.8.2 Latency Stages of Invertebrate Microsporidia -- 4.8.3 Vertical Transmission.

4.8.4 Transovum and Transovarial Transmission -- 4.8.5 Intermediate Hosts -- 4.9 INTERACTIONS WITH OTHER MICROSPORIDIAN SPECIES OR OTHER PATHOGENS -- 4.9.1 Competition among Microsporidian Species -- 4.9.2 Interactions between Microsporidia and Other Pathogens, Parasites, and Environmental Contaminants -- 4.10 HOST SPECIFICITY -- 4.11 EPIZOOTIOLOGY -- 4.11.1 Descriptive Epizootiological Studies in Arthropods -- 4.11.2 Nosema bombi Infections in Bumblebees (Bombus spp.) -- 4.11.3 Hyalinocysta chapmani in Culiseta melanura and Orthocyclops modestus -- 4.11.4 Microsporidia in Arachnid Arthropods -- 4.12 MATHEMATICAL MODELS OF MICROSPORIDIAN EPIZOOTIOLOGY -- Chapter 5 Phylogenetic Place of Microsporidia in the Tree of Eukaryotes -- 5.1 INTRODUCTION: WHY IS THE PHYLOGENTIC POSITION OF MICROSPORIDIA SUCH A PROBLEM, AND WHY SHOULD WE CARE? -- 5.2 ANCIENT HISTORY: FROM DISCOVERY TO THE ARCHEZOA -- 5.3 PROTEIN PHYLOGENY, GENOMICS, AND THE FUNGAL CONNECTION -- 5.4 FUNGI OR SISTERS TO THE FUNGI? -- 5.5 SUMMING UP: WHAT DO WE KNOW AND WHAT ARE THE NEXT QUESTIONS? -- ACKNOWLEDGMENTS -- REFERENCES -- Chapter 6 Phylogeny of the Microsporidia -- 6.1 INTRODUCTION -- 6.2 STRUCTURAL, ULTRASTRUCTURAL, AND ECOLOGICAL CHARACTERS (see Chapters 1 and 2 of this book for details on these characters) -- 6.2.1 Meront -- 6.2.2 Spore Formation -- 6.2.3 Spore -- 6.2.4 Polar Tube (Polar Filament) -- 6.2.5 Life Cycle -- 6.2.6 Host, Host Range, and Host Tissue -- 6.3 HISTORY OF CLASSIFICATION BASED ON PHENOTYPIC CHARACTERS -- 6.3.1 Early History -- 6.3.2 Ultrastructural Advances and Life Cycle Analysis -- 6.4 MOLECULAR PHYLOGENETIC STUDIES -- 6.5 MOLECULAR CLASSIFICATION BASED UPON ssrDNA ANALYSIS OF MICROSPORIDIA GENERA -- 6.6 CONCLUSION -- ACKNOWLEDGMENTS -- REFERENCES -- Chapter 7 Microsporidian Genome Structure and Function.

7.1 INTRODUCTION: WHAT ARE MICROSPORIDIA GENOMES LIKE? -- 7.2 THE SMALLEST MICROSPORIDIAN GENOMES -- 7.3 THE LARGEST MICROSPORIDIAN GENOMES -- 7.4 DIFFERENCES IN CODING CONTENT OF MICROSPORIDIAN GENOMES -- 7.5 IMPACT OF HORIZONTAL GENE TRANSFER IN THE EVOLUTION OF MICROSPORIDIA -- 7.6 EARLY STUDIES OF GENE EXPRESSION IDENTIFY UNUSUAL SPORE TRANSCRIPTS -- 7.6.1 Functional Transcripts and Sequence Signals in Proliferative Stages -- 7.6.2 Introns and Splicing -- 7.7 FUTURE CONSIDERATIONS -- REFERENCES -- Chapter 8 Sex and the Microsporidia -- 8.1 INTRODUCTION -- 8.2 MICROSPORIDIAN ORIGINS AND SEXUALITY -- 8.3 SEXUAL REPRODUCTION IN FUNGI -- 8.4 SEX AND THE MICROSPORIDIAN LIFE CYCLE -- 8.5 MICROSPORIDIAN MEIOSIS -- 8.6 GAMETOGONY AND PLASMOGAMY -- 8.7 PHYLOGENETIC DISTRIBUTION OF PUTATIVE ASEXUAL SPECIES -- 8.8 EVIDENCE FOR RECOMBINATION IN MICROSPORIDIA -- 8.9 GENOMIC EVIDENCE FOR SEX -- 8.10 SUMMARY AND CONCLUSIONS -- REFERENCES -- Chapter 9 Microsporidian Biochemistry and Physiology -- 9.1 INTRODUCTION -- 9.2 BIOCHEMISTRY OF SPORES AND SPORE GERMINATION -- 9.2.1 Spore Germination -- 9.2.2 Energy and Carbon Metabolism in Microsporidia Spores -- 9.2.3 Degeneration of Glycolysis and Other Aspects of Metabolism -- 9.3 METABOLISM IN THE INTRACELLULAR STAGE -- 9.4 THE PLASTIDIC-BACTERIAL ATP/ADP CARRIERS IN MICROSPORIDIA -- 9.5 SECRETORY TRANSPORT -- 9.6 HOST-PARASITE BIOCHEMISTRY -- 9.7 COMPARATIVE MICROSPORIDIAN BIOCHEMISTRY -- 9.8 SUMMARY -- ACKNOWLEDGMENTS -- REFERENCES -- Chapter 10 The Microsporidian Polar Tube and Spore Wall -- 10.1 INTRODUCTION -- 10.2 STRUCTURE OF THE MICROSPORIDIAN SPORE AND POLAR TUBE -- 10.3 POLAR TUBE MORPHOGENESIS -- 10.4 SPORE GERMINATION: ACTIVATION -- 10.5 SPORE GERMINATION: POLAR TUBE DISCHARGE -- 10.6 CHARACTERIZATION OF POLAR TUBE PROTEINS -- 10.6.1 Polar Tube Protein 1 -- 10.6.2 Polar Tube Protein 2.

10.6.3 Polar Tube Protein 3.